Split-sash windows are the type most often used in school buses. They are used in all states and are mandatory in many. Split-sash is a design whereby two panes of glass, an upper and lower pane, constitute the window. Both pieces of glass are typically held with aluminum framing around their perimeters. The lower piece is fixed-in-place and the upper pane slides down to open and up to close. The purpose of the opening is to allow for ventilation. The upper pane is typically held in place with two spring-loaded bolts, located in the top rail of the pane's frame, one on each side of the upper pane. These bolts are plastic and/or metal and protrude from the upper pane and engage ratchets or stops which are part of the outer window frame surrounding the panes. The upper pane is moved by moving the bolts inward and against the spring (lateral pressure), so that the ends of the bolt no longer rest in the notches, and freeing the pane to move up or down. The bolts have finger holds, which are formed-in recesses, that require two hands, one per bolt, to pinch the bolts simultaneously toward each other to free the window.
The present design is inefficient for several reasons. First, a sustained lateral force is needed to free the windowpane in conjunction with vertical force (up or down) to move the pane. Thus the hands are working in a different direction than the arms. Second, the lateral force is against the sides of the fingers, usually the forefinger of each. This is a difficult maneuver to sustain since the strength and natural motion of the fingers is toward the palms. Third, the present window is difficult for small children, as their hands are smaller, their fingers are weaker and their coordination is less developed to handle such a task well. Fourth, the window is more likely to get stuck since the bolts are operated independently. One side can be unlatched and moved down while the other side remains latched binding the window in that position. Fifth, two hands are required to open or to close the window.
The primary objective of this invention is to make a split-sash window that is easier to open and to close than the prior art. This objective is achieved by utilizing a vertical force to release the window by using a latch system that requires only one hand, and by linking the two bolts to a central release so that the window is less likely to bind.
This invention aligns the vertical force of the hand in releasing the bolts with the vertical force of the arm or arms in opening or closing the window. This alignment is achieved by using a window latch system that allows the user to use vertical force to release the horizontally mounted bolts from their stops. Since the window slides vertically, using a thumb-bar that requires vertical force to unbolt the window will allow easier opening, since all forces will be aligned. Present windows use two finger-latches that require horizontal force using two hands. The index fingers are required to push laterally while simultaneously the remaining fingers and thumb raise or lower the windowpane.
The thumb bar requires only one hand to unbolt the window from its stops. In addition to making the window easier to operate, it allows for use with only one hand. Locating the thumb-bar at the center of the top horizontal beam, and connecting both bolts to this one thumb bar, puts the operation interface at one central area on the window, allowing for only one thumb pressing vertically to open the window. Riders with only one hand or one hand free can operate the window.
With the new latch mechanism, the window will be less likely to bind itself into one position. By utilizing one release mechanism for the release of both bolts, there is no longer a requirement for both hands to release each side simultaneously. The single mechanism pulls both bolts inward at the same rate, freeing both sides of the window at the same moment.